The invention relates generally to a system and method of measuring and processing modulated signals, and more particularly to systems and methods for producing digital signals proportional to certain parameters of modulated signals.
Modulators of various types are used to convert an analog input signal to an output pulse train in which pulse density or pulse width or another parameter is proportional to the magnitude and polarity of the input signal. An example of a modulator having high accuracy over a wide dynamic range, and which is therefore suitable for use in electric power metering, is described in copending patent application Ser. No. 518,820, filed Aug. 1, 1983, entitled Pulse Modulator And Method With Wide Dynamic Range, assigned to the assignee of the present invention.
For measurement of power or other waveforms, it is often useful to obtain digital or pulse train representations of certain signal parameters such as full or half wave rectified signal magnitude, signal offset and polarity. It has not heretofore been convenient to extract such parameters particularly in digital form.
It would be advantageous to be able to determine certain useful parameters of an input waveform, such as the overall magnitude of an alternating polarity waveform, the magnitudes of each respective polarity, and average value, from a modulated signal proportional to the input signal. It would be particularly useful to obtain such information from a modulated input signal where the modulation is already performed for other useful purposes, as in the case of power meters, which employ modulations to accomplish signal multiplication.